Despite centuries of scientific study, we still find ourselves constantly discovering new strange and surprising things about our animal brethren. From a trout that fakes an orgasm to a lizard that spews blood from its eyes, we’re honing in on the most extraordinary animal behavior out there.

Crabs that shake pom-poms

These tiny crabs, which measure just an inch or so in size, have long fascinated biologists. The curious creatures, which go by the nicknames of “boxer crabs” and “cheerleader crabs,” are always in possession of two stinging anemones. They clutch the anemones in their front claws, bearing a more than passing resemblance to – depending on which way you look at it – boxing gloves or pom-poms. The reason behind their unusual accessories? According to new research from Bar-Ilan University in Israel, it’s believed that the poisonous anemones help ward off potential predators. When scientists went to Israel's Red Sea and attempted to prize the precious anemones from their grip, the results were astonishing: anemone-less crabs would attempt to steal from fellow crabs, before splitting the stolen anemone into clones. The crab-sea anemones pairing is just one of many fascinating symbiotic relationships that occur in the world’s oceans.

Cows that love compasses

German researchers found that cows were not positioning themselves willy-nilly in their pastures. (Photo: Symbiot/Shutterstock)

Back in 2008, scientists noticed a strange behavior among that most seemingly unremarkable of Earth’s animals: cows. Thanks to a new perspective afforded by Google Earth, they could see that cattle around the world weren’t just standing haphazardly, but rather a significant portion of them appeared to purposefully point themselves either north or south. Which leaves two questions: how and why? The common answer to the first question is that cows, like many other animals, may have magnetoreception, the ability to sense the Earth’s magnetic fields. The answer to why cows align themselves this way, however, remains something of a mystery.

Lizards that shoot blood from their eyes

Of all the peculiar animal behaviors, none are quite as gruesome as that practiced by the horned lizard, whose blood-spurting antics wouldn’t look out of place in a gory Hollywood horror movie. When threatened with attack, this desert-dwelling creature – which can be found in parts of the U.S., Canada, Guatemala and Mexico – spews foul-tasting blood from its eyes in an effort to put off any coyote or bobcat that may be ready to prey. While its bloody tears are an effective defense, they are an 11th-hour option. Horned lizards will do their best to protect themselves in other ways, such as hiding and camouflaging, before pulling this dramatic stunt.

Trout that fake orgasms

Scientists think the tactic of the brown trout could also be an insurance policy against male infertility. (Photo: wwwarjag/Shutterstock)

We humans are complicated creatures. Deception, whether a white lie or something much less innocuous, is widespread in our social interactions. What is perhaps more surprising to learn is that we aren’t the only living creatures on the planet fond of telling a few lies. Scientists from Sweden's National Board of Fisheries discovered that female brown trout have been caught faking orgasms. Though in their defense, the fish seem to have good reason. Biologists speculate that, by not releasing her egg in every instance, the female trout can avoid mating with unsuitable males, attract more partners (and thus increase their chances of successful fertilization) and can avoid wasting an egg on a partner that is not in the right position. Interestingly enough, trout aren’t the only fish to refrain from releasing their eggs; Atlantic salmon were also proved to partake in a similar behavior back in 1954.

Crocodiles that swallow stones

One reason could be that the rocks actually help with digestion. (Photo: Audrey Snider-Bell/Shutterstock)

Take an X-ray of a crocodile’s stomach and there are a few things you can expect to see. It is likely to reveal the remains of fish, birds and any other edible prey they have gobbled, as well as a much more intriguing meal option: a handful of rocks. But why would a crocodile munch down of a pile of pebbles? One thing is for sure, it’s not for nutritional purposes. There are two main theories as to why these scaly reptilians swallow stones. One school suggests the stones add weight, helping them stay underwater, while others say the stones help break down the hard bones of the crocodile’s prey, which they typically eat whole.

Crows that hold grudges

Crows are often name-checked among the brainiest of birds, and rightly so. These black feathered fliers have come up with ingenious survival hacks, including using cars in traffic to help them crack hard-shelled nuts, and making tools to help them get otherwise out-of-reach food. More recently, they have also been credited with a most unusual animal skill: the ability to recognize individual human faces, which means these guys can (and do) hold grudges. The moral of the story? Never cross a crow.